Method for processing multi-component liquid mixtures and device for carrying out said method

ABSTRACT

The present group of inventions relates to processing of multi-component liquid mixtures (MCLM) employing reforming process, preferably for vacuum distillation of hydrocarbon mixtures and in petroleum refining and chemical industries. The inventions include the method for processing of multi-component liquid mixtures. The method of MCLM separation includes pressure feeding of a hydrocarbon liquid mixture to an a liquid-gas jet device nozzle which discharges to a vacuum chamber of liquid-gas jet device. A counter pressure jointly with the liquid-gas jet device forms a pressure surge in the vacuum chamber. The counter pressure is 0.4 to 0.7 of the magnitude of the feed pressure generated by the pump. The plant for MCLM processing includes a feed pump, a head delivery main, a discharge main, control instrumentation and a vacuum-generating device including a vacuum chamber, a liquid-gas jet device with a nozzle in the front end wall of the vacuum chamber. The length of the nozzle exceeds its diameter by a factor 7 to 10. The plant includes a counter pressure regulator connected through a conduit to the rear end wall of the vacuum chamber.

This application is the U.S. national phase application of InternationalApplication PCT/RU02/00566 filed Dec. 27, 2002.

AREA OF THE INVENTION

The present group of inventions relates to processing of multi-componentliquid mixtures employing reforming process, preferably for vacuumdistillation of hydrocarbon mixtures and can be applied in petrochemicaland chemical industries.

STATE OF THE ART

A known method for processing of petrol fraction comprises itsseparation into light and heavy fractions, reforming of the light one atelevated temperature and pressure 0.5 to 2 MPa, extraction of productsyielding aromatic hydrocarbons and raffinate, mixing raffinate withheavy fraction of the secondary reforming at elevated temperature andpressure 2.0 to 4.0 MPa, yielding high-octane component of motor petrol;at that, firstly a fraction boiling away at temperatures 90-93° C. to100-103° C. is extracted from the raffinate and mixed with the heavypetrol fraction, after which the remaining raffinate fractions arefurther fed to mixing with motor petrol component (RU 2080353, IPC C 10G 59/06, 1997-05-27).

However, this method is featured by enhancement of the crackingreaction, which is due to low selectivity of transformation ofhydrocarbons making up the raffinate and to accumulation ofpoorly-reformable hydrocarbons in the circulating flow.

A known method for processing of multi-component mixture of preferablyhydrocarbon composition comprises vacuum feeding of liquid product,resulting in its separation into liquid and gas/vapor phase, evacuationof vapors and gases therefrom with jet suction device with its furtherseparation via condensation into liquid and non-condensed vapor/gasfraction, the latter being further withdrawn for disposal (WO No.96/05900, IPC B 01 D 3/10, C 10 G 7/06, priority date 1994 Aug. 19).

The drawback of this method is utilization of the condensate from theseparator as a working liquid of a jet suction device, resulting inextensive accumulation therein of vapor/gas contaminants, whichessentially deteriorates the output product quality and entailsadditional costs for its after purification.

The closest to the claimed method for multi-component mixturesprocessing in its technological content is the method of vacuumdistillation of hydrocarbon mixtures (crude oil, petrol, etc.),comprising pressure feeding of the incoming liquid mixture into thenozzle of a liquid/gas jet device (hereinafter, a jet device) anddischarging said mixture into a vacuum chamber (RU 2087178, IPC C 10 G7/06, 1997 Aug. 20).

However, this method does not provide sufficiently efficient improvementof the petrol octane number after vacuum distillation of hydrocarbonfluids.

A known plant for processing of hydrocarbon liquid mixtures, forexample, vacuum distillation of crude oil, comprises at least adistillery section under over pressure or atmospheric pressure with anoil delivery pipe, a vacuum column, and a vacuum hydrocyclone unit,comprising an jet device, a separator and a pump for working liquiddelivery. At that, the liquid inlet of the jet device is connected tothe working liquid outlet of the pump, and the gas inlet of the jetdevice is connected to the main for vapor/gas exhaust from the vacuumcolumn with its outlet connected to the separator. The plant is furtherequipped with a second jet device with its liquid inlet connected to thecrude oil delivery main, and its gas inlet connected to the separatorgas outlet, its mixture outlet being connected to the crude oil deliverymain, the inlet of the working liquid delivery pump being connected tothe outlet of the working liquid from the separator (RU 2161059, IPC C10 G 7/06, 1999 Jul. 16).

However, this plant is excessively material-intensive.

The closest to the claimed device for multi-component mixturesprocessing in its technological content is the device for vacuumdistillation of multi-component organic mixtures comprising a deliverypump, an evacuating device, a horizontal vacuum chamber, a head deliverymain and a discharge main, and control instrumentation (RU 2166528, IPCC 10 G 7/06, 1999 Jun. 29).

The drawback of the above device is its insufficient efficiency relatedto high material-intensity and excessive power consumption, and in thedesign aspect, to the layout complexity.

DISCLOSURE OF THE INVENTION

The technological problem, solution of which is the main objective ofthe present group of inventions, is enhancing the efficiency ofmulti-component liquid mixture processing and the devices thereto withthe purpose of obtaining finished product possessing higher quality.

The solution of said problem according to the claimed method is providedfor by the method of processing of multi-component liquid mixturesthrough vacuum distillation comprising pressure feeding of a hydrocarbonliquid mixture to a jet device nozzle with its further discharging tothe vacuum chamber. At that, according to the invention, the incomingliquid mixture is fed to the jet device nozzle under pressure of 1 to 12MPa; due to boiling up of a part of said liquid mixture a two-phasesupersonic flow is generated in the vacuum chamber, after which acounter pressure is applied causing emergence of a pressure surge in thejet device vacuum chamber with avalanche condensation therein of thegaseous component of the two-phase flow.

In the course of the pressure surge, a range of oscillations isgenerated possessing various physical nature, including ultrasonic,electromagnetic, etc., fostering collapsing of newly formed gas bubbles,which in their turn, originate new oscillation while collapsing, thatis, an avalanche process of gas bubbles collapsing occurs generating astrong ultrasonic field, causing transformation of raw liquid mixturecomponents (disintegration, isomerization, etc.).

The solution of the formulated problem according to the second object ofthe claimed group of inventions is provided for by the plant formulti-component liquid mixtures processing comprising a delivery pump, ahead delivery main, a discharge main, control instrumentation andvacuum-generating device comprising a horizontal vacuum chamber. Withthis, according to the claimed invention, the vacuum-generating deviceis embodied as a liquid/gas jet device connected to the head main, thenozzle of which is integrated into the front end wall of the vacuumchamber, the latter having the length with respect to its cavitydiameter meeting the equationL=(7 to 10)*D, where:

-   L is the length of the vacuum chamber,-   D is the diameter of the vacuum chamber cavity;    besides, the plant further comprises the counter pressure regulator    embodied so as to provide for, jointly with the liquid/gas jet    device, conditions for generation of the pressure surge in the    vacuum chamber and connected through a pipeline to the rear end wall    of the vacuum chamber, and a vacuum gauge connected to the vacuum    chamber in the latter's front part.

In the preferred embodiment of the plant, the nozzle is embodied withits thickness with respect to its diameter constituting, where:

$\frac{l_{c}}{d_{c}} = {1\mspace{20mu}{to}{\mspace{11mu}\mspace{11mu}}5}$

-   I_(c) is the nozzle length which in the embodiment of FIG. 1, is    also the thickness of the front end wall (7),-   d_(c) is the nozzle diameter;    besides, connected to the head delivery main between the delivery    pump and the exhaust jet device may be a flowmeter, a thermometer,    and a pressure gauge.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart of the plant I implementing the claimed method ofmineral oil processing.

The plant I for hydrocarbon mixture vacuum distillation (cf. FIG. 1)comprises a horizontal vacuum chamber 1, a delivery pump 2, a headdelivery main 3 and a discharge main 4, a liquid/gas jet device 5,comprising the horizontal vacuum chamber 1 and a nozzle 6, integratedinto the front end wall 7 of the vacuum chamber 1, and a counterpressure regulator 8 connected via a pipeline 9 to the rear end wall 10of the vacuum chamber 1. A vacuum gauge 11 is connected to the vacuumchamber 1 cavity in its front section.

The length L of the vacuum chamber 1 exceeds the diameter D of itscavity by the factor of 7 to 10. With this, the nozzle 6 is preferablyembodied with its thickness l_(c) with respect to its diameter d_(c)meeting the equation

$\frac{l_{c}}{d_{c}} = {1\mspace{14mu}{to}\mspace{14mu} 5.}$

It is expedient to connect to the head delivery main 3 plant controlinstrumentation, that is, a flowmeter 12, a thermometer 13 and apressure gauge 14, between the delivery pump 2 and the jet device 5.

A filter 15 is installed upstream of the delivery pump 2, and deliveryand discharge mains are equipped with valves 16, 17, 18. It is alsoexpedient to install a pressure gauge 19 in the pipeline 9 between thecounter pressure regulator 8 and the rear end wall 10.

Operation of the plant I is carried out as follows.

The hydrocarbon mixture for reforming is fed via the valve 16 and thefilter 15 to the pump 2. The pressure downstream of the pumps ismaintained within the limits 2.0 to 2.5 MPa. The pressure gauge 14, thethermometer 13 and flowmeter 12 monitor the pressure, the temperatureand the flow rate, respectively, of the raw petrol at the workingsegment from the delivery pump 2 fo the horizontal vacuum chamber 1. Atthe startup of the plant operation valves 16, 17 and 18 are open. Therequired evacuation in the vacuum chamber is monitored with the vacuumgauge 11 connected to the front part of the vacuum chamber.

Said value is determined by the saturation pressure of the low-boilingmixture component. For example, for the petrol this value is 0.005 to0.07 MPa at temperatures 4 to 80° C. The maximum counter pressure notaltering the pressure reading of the vacuum gauge is generated with thecounter pressure regulator 8. As a rule, this pressure constitutes 0.4to 0.7 of the pressure generated by the pump 2.

PREFERRED EMBODIMENT OF THE INVENTION

The claimed group of inventions is further illustrated with the Example1, which is by no means limiting with respect to the range of actualtechnologies and devices for their implementation that may be embodiedusing the claimed inventions.

The Example 1 illustrates the method for processing of multi-componentliquid hydrocarbon mixtures and the device for its implementation.

EXAMPLE 1

The raw multi-component hydrocarbon mixture (raw petrol, fuel oil ordiesel oil) constituting a single-phase liquid working medium is fedunder pressure to the jet device.

This pressure has been found to constitute: for raw petrol processing, 1to 12 MPa; for fuel oil processing, 10 to 12 MPa; for diesel oilprocessing. 5 to 6 MPa; for crude oil processing, 4 to 7 MPa.

Due to jet restriction past the output edge of the nozzle 6, which isusually embodied as an aperture (cf FIG. 1), the evacuation is generatedequal to the saturation pressure of the incoming mixture low-boilingcomponent at the given temperature.

The average integral value of saturation pressure of the producedlow-boiling mixture component, e.g. of refined petrol, varies within thelimits of 0.005 to 0.07 MPa and is equal to its saturation pressure atthe temperatures 4 to 8.0° C., which entails originating of a gas phasein the jet liftoff area.

Having passed the nozzle 7, the liquid enters in the reduced pressurearea and boils up, which causes formation of the two-phase gas/liquidflow possessing uniform concentration of the gas phase over the wholevolume of the flow, with said flow further entering the supersonic mode.

The residual pressure in the vacuum chamber is monitored with the vacuumgauge located at the vacuum chamber entrance.

This results in formation of an emulsion with gas bubbles of 0.5 to 7Mpm size, which essentially. creates the second phase of the workingmedium.

Following stabilization of the residual pressure in the vacuum chamber,which is monitored by the vacuum gauge, the maximum counter pressure notaltering the pressure reading of the vacuum gauge is generated with thecounter pressure regulator 8. As a rule, this pressure constitutes 0.4to 0.7 of the pressure generated by the pump 2.

The counter pressure is monitored by the pressure gauge located at thevacuum chamber outlet.

In the course of the further flow motion along the vacuum chamberchannel, the velocity of the flow drops with its pressure rising. Thegaseous component of the two-phase flow, in this case, the distilledhydrocarbon, is condensed and further fed to the accumulator tank.

The overall control of the plant operation is carried out basing on thereadings of the vacuum gauge and the high pressure gauge. With this, togenerate a pressure surge in the vacuum chamber it is expedient toprovide the pressure ratio constituting

${\frac{P_{2}}{P_{1}} > 15},\text{where:}$

P₁ is the pressure prior to the surge (reading of the vacuum gauge forthe residual pressure);

-   -   P₂ is the pressure following the surge (reading of the high        pressure gauge).

Such pressure surge generation has been found to be feasible providedthe ratio of the nozzle cross-section at the output edge level to thevacuum chamber cross-section constituting

${\frac{f}{F} = {0.2\mspace{14mu}{to}\mspace{14mu} 0.6}},\text{where:}$

-   -   f is the nozzle cross-section,    -   F is the vacuum chamber cross-section.

The claimed plant in the preferred embodiment comprises a pump (2), ahorizontal vacuum chamber (1), the length L of which exceeds thediameter of its cavity D by the factor 7 to 10, and a vacuum-generatingdevice (5) embodied as a liquid/gas jet device with a nozzle (6)integrated into the front end wall (7) of the vacuum chamber (1), withthe ratio of the nozzle thickness l_(c) to its diameter d_(c)constituting

$\frac{l_{c}}{d_{c}} = {1\mspace{14mu}{to}\mspace{14mu} 5.}$

The claimed plant further comprises a head delivery main (3), adischarge main (4), equipped with valves (16), (17) and (18) and acounter pressure regulator (8) connected via a pipeline (9) to the rearend wall (10) of the vacuum chamber (1).

The plant is further equipped with control instrumentation, namely, avacuum gauge (11) connected to the vacuum chamber cavity in its frontpart, a flowmeter (12) a thermometer (13) and a pressure gauge (14)connected to the head delivery main (3) between the delivery pump (2)and the vacuum-generating device (5), and a pressure gauge (19)connected to the pipeline (9) between the counter pressure regulator (8)and the rear end wall (10) of the vacuum chamber (1).

Besides, a filter (15) is installed before the feeding pump (2).

The vacuum chamber and the vacuum chamber nozzle can be embodied out ofvarious dielectric materials, e.g. out of plexiglas.

Application of the claimed invention enables obtaining end products of ahigher quality. For example, the petrol octane number is increased inthe average by 2 to 4 units.

Octane number (hereinafter, ON) is a conventional index of detonationcharacteristics of the fuel provided vehicle operation in conditions ofboosted heating mode.

The values of ON presented in Tables 1 and 2 below were determinedthrough motor method in compliance with ASTM D 2699-94, ISO 5163-90, D2700-94 (GOST 511-82, 8226-82).

Mineral oil densities were determined in compliance with ASTM D 4052-91(GOST 3900-85, GOST R 51069-97).

TABLE 1 Comparison of octane number for raw and distilled virgin petrolOct. number of T Q P₁ Octane number ρ¹⁵, distilled ° C. [m³/hr] [MPa]Raw petrol kg/m³ petrol 17 2.4 1.05 78.4 0.735 80.0 17 2.4 1.05 78.40.735 80.0 15 2.4 1.05 78.4 0.734 81.0 17 2.4 1.05 78.4 0.734 81.4 152.4 1.05 78.4 0.734 80.6 14 2.4 1.05 78.4 0.735 82.5 14 2.4 1.05 78.40.734 82.5 14 2.4 1.05 78.4 0.734 83.5 13 2.4 1.05 78.4 0.734 84.0

TABLE 2 Comparison of octane number for raw and distilled casing-headpetrol Oct. Oct. number number T Q Raw Refined ρ¹⁵, ° C. [m³/hr] petrolpetrol kg/m³ 15.7 0.290 65.7 — — 15.7 0.290 65.7 — — 15.9 2.400 65.768.3 0.7151 15.0 1.714 65.7 — 0.7150 15.4 1.714 65.7 — — 15.4 2.400 65.767.3 0.7155 15.4 2.483 65.7 — — where: ρ¹⁵ (kg/m³) is the density of theraw petrol at 15° C.; P₁ (MPa) is the pressure of the raw petrol at theinlet of the plant; Q (m³/hr) is the flow rate of the raw petrol to theplant.

Besides, application of the claimed invention leads to improvements inthe composition and the structure of the incoming product, for example,the molecular mass of the heavy oil fraction is reduced, entailinggrowing of light oil; for instance, output of the fraction up to 360° C.is increased by 3 to 15 percent.

Fractional composition of oil was determined in compliance with ASTM D86-95, ISO 3405-88 (GOST 2177-99).

In addition, physicochemical parameters of both individual fractions andthe last end of the fraction exceeding 360° C. were altered. For examplevirgin fractions of oil refinery products from West-Siberian and Kolguevoilfields show the following factors shown in Tables 3 and 4:

-   -   petrol fractions feature reduction of sulfur content by 9 to 27        percent and increase of the octane number by 0.5 to 0.7;    -   kerosene fractions feature reduction of sulfur content by 6 to 7        percent and lowering of congelation point by 2° C.;    -   diesel oil fractions of light and heavy diesel oil feature        reduction of sulfur content by 5 to 19 percent and lowering of        cloud temperature by2 to 3° C.

TABLE 3 Comparison of raw (a) and distilled (b) virgin fractions ofWest- Siberian oilfield raw oil. Kerosene Diesel oil Diesel oil Petrolfraction fraction fraction fraction (180° C.) (120-240° C.) (180-320°C.) (180-360° C.) Indices a b a b a b a b West-Siberian oilfield raw oilDensity ρ²⁰, 745 741 777 774 829 826 848 845 kg/m³ ON 48.7 49.4 — — — —— — Sulfur 0.082 0.075 0.15 0.14 0.37 0.35 0.42 0.40 content, %Congelation — — −57 −59 — — — — point, ° C. Cloud — — — — −32 −34 −26−28 point, ° C.

TABLE 4 Comparison of raw (a) and distilled (b) virgin fractions ofKolguev oilfield raw oil. Kerosene Diesel oil Diesel oil Petrol fractionfraction fraction fraction (180° C.) (120-240° C.) (180-320° C.)(180-360° C.) Indices a b a b a b a b Kolguev oilfield raw oil Densityρ²⁰, — — — — 803 800 811 808 kg/m³ ON (MM) 48.8 49.3 — — — — — — Sulfur0.011 0.008 — — 0.062 0.05 0.07 0.06 content, % Cloud — — — — −35 −38−28 −31 point, ° C.

Sulfur mass content (%) was determined in compliance with ASTM D1266-91, ASTM D 2622-94, ASTM D 4294-90, ISO 8754-92.

Cloud point (point of crystallization onset) was determined incompliance with GOST 50066-91.

The essence of the method is refrigerating of a fuel sample in adouble-walled test-tube equipped with a thermometer and determining ofthe cloud point without visible formation of crystals.

Congelation point was determined in compliance with GOST 50066-91.

The essence of the method is refrigerating of a fuel sample in adouble-walled test-tube equipped with a thermometer and determining ofthe point of formation of crystals.

TABLE 5 Table of fractional distillation of oil. Sample # 0 (Raw oil) 12 3 4 5 6 7 8 Density at 20° C., kg/m³ 898 900 899 900 900 899 900 900898 Fractional composition, ° C. T_(ob) 77 83 64 85 79 67 82 65 71 10%161 163 158 161 158 159 156 154 158 20% 219 219 217 218 221 218 208 217215 30% 266 265 264 265 264 264 257 264 262 40% 306 305 302 306 306 304305 305 303 50% 347 341 338 345 344 340 336 345 340 60% 355 357 359Yield of 14 13 14 14 13 13 15 13 14 fractions up to 180° C., % Yield of17 17 17 17 16 17 18 17 17 fractions up to 200° C., % Yield of 56 61 5956 58 64 62 58 62 fractions up to 361° C., % T_(ob) being thetemperature of boiling onset.

It follows from the data of Table 5 that the process implementation incompliance with the claimed invention entails systematic growth of lightfractions yield.

Fuel oil refining using the claimed method enables their refining intolight oil fractions.

INDUSTRIAL APPLICABILITY

The inventions are industrially applicable, as they provide foremployment of standard commercial industrial equipment and industrialhydrocarbon mixtures produced at mineral oil refinery in petrochemicaland chemical industries.

1. A plant for multi-component liquid mixtures processing comprising afeeding pump (2), a head delivery main (3), a discharge main (4),control instrumentation (11, 12, 13, 14, 19) and a vacuum-generatingdevice (5) comprising a horizontal vacuum (1), wherein thevacuum-generating device (5) is implemented as a liquid-gas jet device(1, 5, 6, 7, 10) connected to the head main (3), a nozzle (6) of whichis integrated into a front end wall (7) of the vacuum chamber (1),having a length with respect to its cavity diameter meeting the equationL=(7to10)*D, where: L is the length of the vacuum chamber, D is thediameter of the vacuum chamber cavity; the plant further comprises acounter pressure regulator (8) implemented so as to provide for, jointlywith the liquid-gas jet device (1 5, 6, 7, 10), formation of a pressuresurge in the vacuum cambered and connected through a pipeline to a rearend wall of the vacuum chamber (1), and a vacuum pressure gauge (11)connected to the vacuum chamber (1) in a front section of said vacuumchamber.
 2. The plant according to the claim 1, wherein the nozzle (6)has a length with respect to its diameter constituting${\frac{l_{c}}{d_{c}} = {1\mspace{14mu}{to}\mspace{14mu} 5}},\text{where:}$l_(c) is the nozzle length, d_(c) is the nozzle diameter.
 3. The plantaccording to claim 1, wherein additionally connected to the headdelivery main (3) between the feeding pump (2), and the liquid-gas jetdevice (1, 5, 6, 7, 10) are a flowmeter (12), a thermometer (13), and apressure gauge (14).
 4. The plant according to claim 2, whereinadditionally connected to the head delivery main (3) between the feedingpump (2) and the liquid-gas jet device (1, 5, 6, 7, 10) are a flowmeter(12), a thermometer (13), and a pressure gauge (14).
 5. A method forprocessing of multi-component liquid mixtures by vacuum distillationcomprising pressure feeding a feed hydrocarbon liquid mixture to anozzle of a liquid-gas jet device which comprises said nozzle and avacuum chamber, said nozzle discharge into said vacuum chamber, saidfeed hydrocarbon liquid mixture is pumped to said nozzle at a feedpressure or 1 to 12 Mpa which is generated by pump, wherein due tovaporization of a part of said feed liquid mixture a two-phasesupersonic flow is formed in said vacuum chamber, and then a counterpresser is generated which causes a pressure surge in said vacuumchamber with avalanche condensation therein of a gaseous component ofsaid two-phase flow, said counter pressure is 0.4 to 0.7 of themagnitude of said pressure generated by said pump.
 6. The method ofclaim 5, wherein said feed hydrocarbon liquid mixture is a liquidpetroleum mixture.